Phytoplankton production and chlorophyll distribution in the eastarn and central Arabian Sea in 1994-1995

Abstract

Measurements of primary production, chlorophyll a, particulate organic carbon (POC) and nitrogen (PON) were carried out during the inter-monsoon winter monsoon and summer monsoon seasons of 1994-95 in the central and eastern Arabian Sea. The integrated production rate varied between 193-199, 337-643 and 770 mgCm sup(-2) d sup(-1) respectively in the open ocean (along 64 degrees E) for the three seasons. The corresponding values in near coastal stations were 281-306, 200-807 and 440-1760 mgCm sup(-2) d sup(-1) . Column chlorophyll a values for these seasons were between 8-17, 13-27 and 34-44 mgm sup(2) for near coastal waters. A subsurface chl maximum (SCM) at approx 40-60 m was conspicuous during the intermonsoon period. The seasonal variation in productivity was consistent with the circulation patterns and associated nutrient levels. Phytoplankton and zooplankton (as carbon) contributed 10-22% of POC. Estimated division rate of phytoplankton varied from 0.7 to 3 for different seasons and locations.